Data storage system connectors with parallel array of dense memory cards and high airflow

ABSTRACT

Data storage system connectors are described for a parallel array of dense memory cards that allow high airflow. In one example, a connector has a horizontal plane board having a plurality of memory connectors aligned in a row and a plurality of external interfaces, a plurality of memory cards, each having an edge connector at one end of the memory card to connect to a respective memory connector of the board, each memory card extending horizontally parallel to each other memory card and extending vertically and orthogonally from the board, and a plurality of interface connectors each to connect an edge connector to a respective board connector, the interface connectors extending horizontally from the one end of the memory cards and vertically to the respective plane board connector.

CLAIM OF PRIORITY

This application is a U.S. National Phase application under 35 U.S.C. §371 of International Application No. PCT/US16/22295 filed Mar. 14, 2016,entitled “DATA STORAGE SYSTEM CONNECTORS WITH PARALLEL ARRAY OF DENSEMEMORY CARDS AND HIGH AIRFLOW” the entire contents of which areincorporated herein by reference.

FIELD

The present description pertains to the field of data storage systems,and in particular to a system with an array of memory cards.

BACKGROUND

High capacity, high speed, and low power memory is in demand for manydifferent high powered computing systems, such as servers, entertainmentdistribution head ends for music and video distribution and broadcast,and super computers for scientific, prediction, and modeling systems.The leading approach to provide this memory is to mount a large numberof spinning disk hard drives in a rack mounted chassis. The chassis hasa backplane to connect to each hard drive and to connect the hard drivesto other rack mounted chassis for computation or communication. The harddisk drives connect using SAS (Serial Attached SCSI (Small ComputerSystem Interface)), SATA (Serial Advanced Technology Attachment), orPCIe (Peripheral Component Interface express) or other storageinterfaces.

While the spinning disk hard drive provides a large amount of storage atlow cost, it has a high power consumption, reliability issues and highheat production. This is not significant for desktop computers with asingle drive but when hundreds or thousands of drives are combined, thenthe power required to drive and cool the disks can be significant. NANDflash drive prices are coming down steadily while reliability andlongevity is being improved. As a result, for many applications an AFA(All Flash Array) is used for either hot, warm or cold storageapplications or all.

Flash arrays are constructed at high volume in a 2.5″ hard disk driveform factor and in a M.2 module form factor. These form factors havebeen specifically developed for notebook computers and provide an amountof storage, speed, power consumption and cost that is best suited fornotebook computers. An AFA could be built using these standard formfactor SSDs (Solid State Drives). When off the shelf 2.5″ SSDs are usedfor a large capacity solution and they are vertically mounted there is aminimum rack-mount chassis size of 2 U or 3 U due to the size of thedrives, the mounting connectors and the need for airflow. M.2 SSDs havea lower capacity and so require many more devices and connectors.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example, and not by way oflimitation, in the figures of the accompanying drawings in which likereference numerals refer to similar elements.

FIG. 1 cross-sectional side view diagram of memory system according toan embodiment.

FIG. 2 is an isometric view of a memory system with a top cover removedaccording to an embodiment.

FIG. 3 is a top plan view of a memory system with a top cover removedaccording to an embodiment.

FIG. 4 is a side plan view of a memory card according to an embodiment.

FIG. 5 is a top plan view of the memory card of FIG. 4.

FIG. 6 is a cross-sectional side view diagram of an alternative memorysystem according to an embodiment.

FIG. 7 is an isometric view of another alternative memory systemaccording to an embodiment.

FIG. 8 is an isometric diagram of a portion of a row of memory tomidplane connectors and a memory card according to an embodiment.

FIG. 9 is an isometric diagram of two different configurations of amemory to midplane connectors according to an embodiment.

FIG. 10 is a side view diagram of the rear edge of a memory cardaccording to an embodiment.

FIG. 11 is side view diagram of a memory to midplane connector with afirst z-height according to an embodiment.

FIG. 12 is side view diagram of a memory to midplane connector with asecond z-height according to an embodiment.

FIG. 13 is an isometric diagram of a portion of a memory card and analternative memory to midplane connector with connections to two memoryplanes according to an embodiment.

FIG. 14 is an isometric diagram of a portion of a row of alternativememory to midplane connectors according to an embodiment.

FIG. 15 is an isometric diagram of the memory to midplane connectors ofFIG. 14 from the opposite side according to an embodiment.

FIG. 16 is a block diagram of a computing device incorporating a memorysystem or capable of accessing a memory system according to anembodiment.

DETAILED DESCRIPTION

A memory system is described that provides a new connector for densememory system designs, such as All Flash Array (AFA) designs, and othernon-volatile or volatile high density memory systems. The system offersfront serviceability of the storage modules, as well as excellentairflow characteristics. Instead of using M.2 form factor or 2.5″ formfactor SSDs that require a top serviceable model for a very densesolution. The system described herein has front or top serviceability ofthe array of flash storage modules, as well as excellent airflowcharacteristics. The front serviceable storage modules avoid the needfor the chassis to slide out of the rack because there is no need toopen the top cover to service the storage modules. Yet the system maystill be mounted to a sliding carrier to allow for other modules to beserviced without removing the chassis, such as fans, interconnects,controllers, switches, and computing modules. The front access to thestorage modules reduces cost, time, and risk when storage modules arereplaced or reconfigured.

As described dense memory storage boxes have high airflow, heatdissipation and storage density using a thin and long SSD form factor.This SSD will be referred to herein as a “Ruler Storage Module”, “RSM”or “ruler”. Several RSMs may be used in a 19″ wide rack-mount SSDsystem. They may be placed in a single row multiple column arrangement,which helps guide the airflow and provides maximum surface area for theNAND media.

FIG. 1 is a cross-sectional side view diagram of an example of arack-mount chassis 201 and enclosure to accommodate the RSM's asdescribed herein. The system has an enclosure 102 which in this case isa 1 U height rack mount enclosure. The enclosure is configured to mountin a particular type of standardized rack that has airflow from thefront or left as shown in the diagram to the rear or right as shown inthe diagram. The rear is configured for cabling. The 25 enclosure isabout 19″ (483 mm) wide and 33″ (840 mm) deep. The 1 U form factor is1.75″ (44 mm) high. However, the particular width, height, and airflowdirection may be adapted to suit other form factors.

The enclosure 102 carries a system module PCB (printed circuit board)104 proximate the rear of the enclosure, a midplane PCB 106 near themiddle of the enclosure and an array of RSMs (also referred to herein as“ruler SSDs” and “memory cards”) 108 proximate the front of theenclosure. An array of fans 110 is mounted to the front of the enclosureto draw air into the enclosure and push it between and across the RSMsand to the rear of the enclosure. One or more power supplies 112 aremounted at the rear of the enclosure and may also have fans to draw airfrom the enclosure and push it out the rear of the enclosure. There maybe additional fans along the chassis from front to rear. Rear fans maybe used to pull air from the front across the chassis. Fans may be usedin the middle of the chassis in addition to or instead of the front orrear fans to pull air in from the front and push it out the rear.

The configuration may be considered to have three zones a front memoryzone 170 that in this example is about 16″ (400 mm) deep, a centralmidplane zone 172 that is about 8″ (200 mm) deep and a rear power supplyand compute zone 174 that is also about 8″ (200 mm) deep. The relativesizes of these zones may be adapted to suit different configurations.The memory array consumes about half of the enclosure so that the rearhalf of the enclosure may be configured to suit different applicationsof the system.

In the memory card zone 170, the parallel memory cards extend from aposition proximate the front of the enclosure toward the rear of theenclosure. This is followed by the switching zone 172 proximate thefront of the enclosure and connected to the memory cards to carry aswitch fabric. This is where the midplane lies. The rear zone 174 haspower supply and management between the memory card zone and a rear ofthe enclosure. This zone may also be the switch zone that carries theswitch fabric. In this case the midplane carries only a connector matrixto couple the power supply and management zone to the memory card zone.This middle zone may also be a compute zone which performs computationsusing values stored in the memory card zone.

The system may also be considered to have a rear fan zone 176 betweenthe power supply and management zone and the rear of the enclosure topull air from the memory card zone out the rear of the enclosure. Therear fan zone cooperates with a front fan zone 178 between the memorycards and the front of the enclosure to push air from outside theenclosure to the memory card zone.

The front fans and the rear power supply provide a push of air from thefront and a pull of air from the rear to establish air flow across theRSMs, the midplane and the system module. The number and arrangement ofthe fans may be modified to suit the cooling and module requirements ofthe system. The system may have no front fans or no power supply fansand rely only on the push or the pull or both. While common powersupplies include fans, the power supplies may not have fans. Insteadseparate rear fans may be used. Additional rear fans may be used tosupplement the pull of the power supply fans. In some embodiments, thepower supplies are provided in a separate enclosure and rear fans may beused without power supplies.

The system module 104 may be provided to suit different requirements,depending on the intended use of the system. The system module may be adata interface or a switching interface to connect the RSMs to externalconnectors through wired or wireless interfaces. It may include a memorycontroller to manage access to the RSMs and provide memory managementand maintenance. It may include a data processing system to provideserver, computing, and other functions between the RSMs and externaldevices.

The mid plane 106 provides a connection between the RSM's and the systemmodule, including a power interface to the RSMs. As shown, there is aconnector (also referred to herein as a “card connector” and a “cardedge connector”) 181 at the end of each RSM and a connector (alsoreferred to herein as a “slot connector”) 183 on the midplane for eachRSM. An interface connector 182 connects each RSM to each midplaneconnector. The end connector allows the RSM to be pulled laterally orhorizontally out of the interface connector and out of the chassis withno upward movement.

The midplane may also provide memory management and mapping between theRSMs and the system module. As shown, the midplane PCB is mountedhorizontally and orthogonal to the RSMs. The horizontal orientation ofthe mid-plane eliminates the need to design cavities into the midplaneto accommodate air flow. This greatly simplifies midplane design andsignal routing.

The RSMs 108 contain all the flash memory, such as NAND flash and thememory controllers that are needed to store user data. Each RSM alsoworks as part of an airflow channel for guiding the air that is blown inby the front mounted fans and blown out by the fans in the powersupplies in a push-pull model. By using thin and long form factor SSDsin a single row format, the surface area of the SSD card is maximized,with excellent airflow characteristics. By using the interface connectorbetween the horizontal midplane and the orthogonal RSM, air can flowbetween the interface connectors to the rear of the chassis.

With the vertical and parallel flash modules extending orthogonal to themidplane, the storage may be very dense. All the area is beingeffectively used, with excellent airflow characteristics. Using 32 RSMswith 32 TB capacity in a 19″ SSD enclosure, the system could have astorage density of up to 1 PetaByte in a 1 U height rack chassis.Emerging 3D NAND chips allow for 1 TB of NAND memory on a single chip.By placing 18 such chips on each side of each RSM and placing 32 RSMs inthe enclosure a 1 U 19″ Storage system can replace two full racks of 1TB HDDs. The parallel orthogonal RSM configuration allows for very tightRSM-to-RSM spacing so that more RSMs may be fit into a single chassissystem enclosure while maintaining very good air flow for systemcooling.

FIG. 2 is an isometric view diagram of a variation of the system of FIG.1 with the top cover and side walls of the enclosure removed. There areseveral fans (not shown) in the front pulling air from outside, followedby 32 Ruler SSDs 108 followed by modular connectivity and computemodules at the back. There are two redundant power supplies 112 on thesides at the back of the enclosure. These power supplies have fans whichare pushing air out of the box.

The memory, storage rulers, or RSMs are carried and supported by abottom plate 120 of the enclosure. The bottom plate provides verticalsupport and may also have grooves or slots (not shown) to hold each RSMin place including to hold the rulers parallel to each other to supportair flow. The RSMs are attached to the midplane by connectors 181 at therear for data communications and power with the midplane. There is alsoan array of slot connectors 183 in the horizontal midplane to attachthrough interface connector 182 to the rear edge of the RSMs. Theinterface connectors do not interfere with airflow between the RSMs. Themidplane may also have slots or grooves to guide and hold the bottomedge of the RSM in place.

The system board 104 in this example is an interchangeable componentthat may be selected for different connection configurations. As shown,there are four system boards. Each one has a switching complex 134 toprovide switching between the different RSMs and an interface 128 thatprovides connections to external components. The interface may take anyof a variety of different forms depending on the system needs. Theinterface may be a network interface, a storage array interface, or adirect memory connection interface.

PCIe (Peripheral Component Interconnect express) interconnect with anNVMe (Non-Volatile Memory express) storage protocol may be supported bythe switching fabric 134 and the external interface 128. In this case,the NVMe is supported at the external interface and may also besupported in the connection to each RSM as well as within each RSM.Other PCIe interconnect protocols may alternatively be used. In additionSAS (Serial Attached Small computer system interface), SATA (SerialAdvanced Technology Attachment), or other related, similar or differentstorage protocols may be used.

FIG. 3 is a top view diagram of a further variation of the memory systemof FIG. 2. A high level architecture is shown of a variation of a 19″SSD. The array of fans 110 are at the front of the enclosure and blowair across the array of SSDs 108. In this example there are 10 fans toblow air across 32 SSD memory cards. The precise number of fans may beadapted to suit the dimensions of the enclosure and particular type andconfiguration of fan and any other guides, shrouds, or other structures.The cards are placed vertically and aligned to be parallel to eachother. The cards connect to a midplane 106 that has 32 connectors 183,one for each card. The connectors are at the rear end of the card. Theconnector may take a variety of different forms. The midplane isconnected to a system module. The system module PCB is not visible inthis view because it is covered by other components.

The midplane is coupled through a power connector 136 on left and rightsides of the midplane (top and bottom as shown) to a left and right sidepower supply 112. These power supplies may be complementary or redundantand the midplane may be wired so that both power supplies are coupled toeach RSM.

The midplane base board is also coupled through an array of dataconnectors 130 to two switching modules 134. The left module serves the16 RSMs on the left and the right module serves the 16 RSMs on theright. The RSMs may also be cross-coupled so that each RSM is coupled toboth modules or connected in any of a variety of different patterns thatinclude various types of redundancy.

The switching modules may contain any of a variety of differentcomponents, depending on the implementation. In this example, there is aPCIe switch 126 for each module and a network interface card (NIC) 128for each module. The NICs allow for an Ethernet connection to externalcomponents. The Ethernet connection is converted to PCIe lanes for theRSMs. Each RSM may use one or more lanes of a PCIe interface dependingon the speed and the amount of data for the particular implementation.The switching modules may also include system management sensors andcontrollers to regulate temperature, monitor wear and failures andreport status. While switching modules are shown, other types of modulesmay be used including server computers that use the RSMs as a memoryresource.

FIG. 4 is a side plan view diagram of an RSM or memory card 108 suitablefor use with the memory system as described herein. The card has aprinted circuit board (PCB) structure 150 with a connector 171 to themidplane at one end. Multiple memory chips 154, in this case eighteenchips are mounted to one side of the PCB structure. There may be more orfewer depending on the application. Each memory chip generates heat withuse and consumes power with read and write operations. The number ofchips may be determined based on power, cost, heat, and capacitybudgets. In some embodiments 3D NAND flash memory chips are used.However, other types of solid state memory may be used including PCM(Phase Change Memory), STTM (Spin Transfer Torque Memory), magnetic,polymer, and other types of memory.

The memory card further includes memory controllers 156 to controloperations, manage cells, mapping, and read and write between theconnector 152 and the memory chips 154. Fan out hubs 158 may be used toconnect the memory controllers to the cells of each memory chip. Buffers160 may also be used to support write, read, wear leveling, and moveoperations.

FIG. 5 is a top view of the memory card of FIG. 4 showing the samecomponents. The card may be configured to support more memory chips onthe other side or only one side may be used, depending on the budget forpower, heat, and capacity. The memory card may have heat sinks andexposed chip package surfaces as shown, or may be covered with one ormore larger heat sinks or heat spreaders as well as protective covers.

The particular configuration and arrangement of the chips may bemodified to suit requirements of different chips and to match up withwiring routing layers within the PCB. The buffers may be a part of thememory controllers or in addition to those in the memory controllers.There may be additional components (not shown) for system status andmanagement. Sensors may be mounted to the RSM to report conditions tothe memory controller or through the connector to an external controlleror both.

The RSM allows a large amount of NAND flash memory to be packed into asmall design. In this example with 1 TB of memory per NAND chip 154, 36TB of memory may be carried on a single memory card. This amount may bereduced for lower cost, power, and heat and still use the same formfactor. The Ruler Storage Module is shown with an end connector. Thisallows modules to be replaced without removing a top cover of thechassis even for a top serviceable enclosure. The memory modules may beremoved and replaced simply by moving fans or access panels at thefront. Typical equipment racks allow the enclosure to slide forward toallow access without removing the enclosure from the rack but this isnot required to service only the memory.

The Ruler Storage Module provides optimized airflow and a maximalsurface area for storage media. This new storage module allows for a 1 Uhigh, extremely dense SSD solution. This new storage module form factordoes not hinder airflow in the system and yet is dense enough to providea great advantage over existing form factors that were developed forother purposes, such as 2.5″ notebook drives, AIC (Advanced IndustrialComputer) memory, M.2 cards, and Gum-stick memory (typical USB stickstyle configurations). Some of these form factors cannot be used in a 1U height enclosure in any arrangement.

The RSMs provide quick and secure connections and may be configured tobe hot-swappable in some systems. Using modular compute and connectivityblocks for the 19″ SSD system described herein, one can easily, withoutsystem shut-down, swap out a compute module and insert a new computemodule with varying compute horse power, depending upon the storagesolution requirements, within the 19″ SSD enclosure. For example, a lowpower compute module, such as an Intel® Atom® processor-based system maybe used for storage targets that need mid-range compute capabilities,such as Simple Block Mode Storage, NVMe over Fabrics, iSCSI/SER, FiberChannel, NAS (Network Attached Storage), NFS (Network File System), SMB3(Server Message Block), Object store, distributed file system etc. Ahigher performance processor on the compute module may be used for Cephnodes, Open Stack Object, Custom Storage Services and Key/Value Stores.For very high performance, the computing module may be in a differentenclosure on the same or another rack and connected using PCIe switchesor another memory interface.

In addition to providing interchangeable RSMs, the same chassis andenclosure may allow for the system modules to be interchangeable. Thismay allow for different connectivity modules to be used. The system maybe upgraded to a different storage protocol (e.g. NVMe over Fabric RDMA(Remote Direct Memory Access), iSCSI (internet SCSI), NVMe, PCIe, oreven Ethernet) without changing any of the RSMs. This modularity alsoenables two modules to be used for redundancy and fail-over in someapplications (e.g. traditional enterprise storage) and a single modulefor other applications (e.g. cloud computing).

FIG. 6 is a diagram of an alternative chassis enclosure for a 2 U (3.5″or 89 mm) rack height. In this enclosure, the same memory cardconfiguration is used for lPB plus of storage. The additional heightallows for additional computing and switching components to be includedwith short fast connections to the memory. In this example, there is anarray of memory cards 208 proximate the front of the enclosure coupledthrough connectors 281, 282, 283 to a midplane PCB 206 near the centerof the enclosure. The midplane is coupled through connectors 214 to asystem module PCB 204 at the rear of the enclosure. There is a front fanzone with an array of fans 210 to push air across the memory cards 208and a rear power supply 212 fastened to or adjacent to the system modulePCB 204 proximate the rear of the enclosure to pull air out of thechassis 601.

In contrast to the 1 U configuration, the system module may be on eitherthe lower or upper side of the enclosure. The RSMs have the sameconfiguration and therefore use only one half of the 2 U chassis. Inthis example, the RSMs are in the lower half of the enclosure but couldalternatively be in the upper half. The system module is in the upperhalf opposite the RSMs. Due to the PCB structure of the midplane and thesystem module, the PCBs are in the center of the enclosure andhorizontal while the components on the PCBs extend vertically from thePCBs into the upper half of the enclosure. An additional system module(not shown) may also be added to the lower half of the enclosure at therear of the enclosure.

The 2 U configuration also allows an additional system module PCB 216 tobe added at the front of the enclosure above the RSMs. As mentioned, theRSMs may be in the upper half, in which case, the additional systemmodule may be in the lower half instead. The additional system modulemay be used to provide computing power or additional switch fabric. Asan example, the rear system module may be used as interface, switchfabric, and power supply, while the front system module is used as acomputing zone with microprocessors and memory for low power or highpower computing. Alternatively, the front system module or an additionalrear module may be used for PCIe adapter cards for graphics rendering,audio or video processing, or other specialized tasks.

FIG. 7 is an isometric diagram of an alternative chassis enclosure for a1 U rack height. This configuration may be augmented by an extra layerfor additional computing, switching, interface, or power supplyresources. The front of the chassis has a memory or RSM zone 302. Inthis example, the rulers are covered by a top cover 320 which may alsoact to guide air across and between the rulers. A horizontal plane boardin the form of a midplane 304 is directly beneath and coupled to therulers. The rulers extend orthogonally upward from the top side of themidplane. A power supply and management zone 305 includes power supplies307 on either side of the enclosure. Compute modules 310 are placedside-by-side between the power supplies 307 and proximate the rear ofthe enclosure. The compute modules include external interface componentsthat couple to cabling. The cabling connects the memory system toexternal component on another position on the rack or to another rack.As in all of the other embodiments, the compute modules may be limitedto serving and storing data and converting to and from differentformats. The compute modules may be more powerful and able to performsimple tasks at low energy or more complex computation and modelingtasks, depending on the particular implementation. A fan zone 314 isplaced near the center of the enclosure with an array of fans 323 acrossthe width of the chassis. There are seven fans in this example, butthere may be more or fewer as mentioned above. The fans pull air fromthe front of the chassis between the memory rulers and then push it outthe rear of the enclosure. They may be helped by the power supply andcompute module fans, if any, and by additional rear fans, if any. Theintermediate fan zone is placed between the memory rulers and the powersupplies on the same side of the midplane as the memory rulers.

FIG. 8 is an isometric diagram of a portion of a row ofmemory-to-midplane connectors (e.g., connectors 181, 182, 183, 281, 282,283) in more detail. In this diagram there are three card connectors181, each coupled to an interface connector 182, and one memory card302. In the illustrated examples, this is just a portion of theconnectors that may be used for all 32 memory cards, however, the numberand positioning of the memory cards may be adapted to suit differentcircumstances. The memory card 302 may be made of a variety of differentprinted circuit board 5 materials. The end of the card may be formed ofthe PCB material or a special attachment fixture may be fastened to theend of the card that has a configuration similar to that shown. The endof the memory card as shown has a slot 304 at the top and the bottom ofthe edge of the card and a set of copper contacts between the two slots.

The slots 304 at the top and the bottom of the rear or back edge of thememory card are defined, in part, by fingers 308 that extend from theends of the card. The fingers and the slots mate with correspondingconstructions in the card connector 181. The connector has a card slot312 for the memory card that extends vertically and orthogonal to themidplane and has a set of matching conductors to make electrical contactwith the memory card. The connector is formed of a suitable polymermaterial that is moderately compliant so that the memory card is wedgedinto the slot of the connector. The conductor provides a data connectionbetween the midplane and the memory card and may also provide power,control, system management and other types of service and communicationbetween the midplane and the memory card.

The connector 312 further includes a guide 314 at the top and the bottomwith angled leading edges 316. The leading edges push the fingers of thecard into alignment so that the electrical contacts are aligned. Theguides then hold the card in alignment after the connection is made. Theguides have a stop 318 at the back. As the card is pushed into theconnector, the fingers are pushed into proper alignment. The anglededges of the fingers 308 push the card into horizontal alignment and themovement of the card is stopped when the fingers are pushed against therespective stops 318 at the back of the connector. The finger is limitedin its horizontal movement when it hits the stop at the back of theguide. With two fingers one, at each end of the card, the stops ensurethat the memory card is moved into its proper position in the interfaceconnector socket when the fingers hit the stops.

The connector also optionally carries bus bars to provide a commonconnection for multiple memory cards for power (bus bar 324) and forground (bus bar 322). The bus bars extend across and through all threeconnectors and rest within a respective ledge 328, 326 of each connectorfor a common power supply for all three memory cards. The bus bars mayextend across all 32 connectors in a chassis or the bus bars may bedivided into sections based on the power supply, the memory interface oranother criterion. With a single power and ground bus bar for all of thememory cards, the bus bars may be used to bridge power from multiplepower supplies. With bus bars that each serves, for example, eightconnectors each, the bus bars may be isolated to particular groups ofmemory cards to aid with memory card management as groups. The bus barsmay be fastened in place so that they are not moved by the insertion orremoval of a memory card.

When bus bars are used each memory card may be configured so that thefinger 308 at each end of the rear edge of the card engages a respectivebus bar. In this case, the upper finger is pushed upward by the upperground bus bar and the lower finger is pushed downward by the lowerpower bus bar. The counter direction forces push the memory card both upand down to secure the memory card in a vertical position. As shown eachfinger also has a metal contact 330 to electrically engage therespective bus bar and conduct the power to wiring layers of the memorycard. Using the bus bars and the fingers, the memory card may be wedgedinto place and secured against vertical movement. The memory card isalso wedged into place in the slot of the connector to secure the cardagainst horizontal movement.

While only top and bottom power bus bars (Vdd and GND) are shown, thesebars may be at a different position on the connector and there may bemore or fewer bus bar connectors. The electrical contacts in the slotmay be used to provide one or the other of the power supplies or toaugment the power supply with other voltages or frequencies.

The connector body and bus bar elements may be engineered to naturallyguide and align the RSM into a mating position with high precisionduring insertion into the system. This allows additional alignmentcomponentry such as guide pins and sockets to be avoided. Even with thebus bars there is still a significant amount of vertical space for theslot and the electrical connections. These may be copper or goldfingered matings.

As an example, for a roughly 1 U (about 40 mm) high RSM, with 0.8 mmpitch and with about 15 mm for the bus bar fingers more than 30 pins orcontacts may be accommodated on each side of the connector or 60 pins onboth sides. 60 pins is more than enough to support a variety ofdifferent data and control signalling connections such as 4 lanes ofPCIe Gen3 or Gen 4, e.g. PCIe G4. PCIe may be configured as a single 1X4 port, or 2 X2 active dual ports. There are also enough pins for up to2 ports of 2.5 Gbs Ethernet (2.5 GE).

Finally an interface connector (also referred to as a quarter-circleconnection) 182 is provided at the back of each connector 181 for a thinprofile connector that does not restrict airflow on either side of eachmemory card. This allows the connector body to be very narrow. Air flowis not impeded since the data signals are routed through the connectorand power is provided using the top and bottom bus bars. The narrowquarter circle connectors also allow for a very tight RSM-to-RSM spacingso more modules can be fit into a system while maintaining very good airflow for system cooling. While these connectors are shown as anddescribed as quarter-circle connectors they may take any of a variety ofother shapes to connect a vertical connector to a horizontal connector.

As shown, the memory cards extend horizontally from the front toward therear of the enclosure and each memory card extends vertically from thehorizontal midplane board. The quarter circle connectors similarlyextend horizontally from the edge connector at the end of each memorycard and also vertically from the horizontal midplane board. The quartercircle of the interface connectors provides a transition from thehorizontal to the vertical but since the PCB of each interface connectorextends from the end of each card and is vertically aligned and parallelwith the respective memory card, airflow between the memory cards alsoflows between the vertical and parallel interface connectors.

The bus bar power distribution allows for a very high current to beprovided to each RSM. The high level of power allows for large memoryarrays and high speed routing and control devices. The bus bars may beused to provide more power than the contacts within the slot connectoris able to sustain. As a result, higher capacity and higher speed memorycards may be used as memory density continues to improve.

In addition, the bus bar power distribution system protects the midplanestructure from potential damage in the case of an electrical short in ahigh power RSM module. Damage is confined to the RSM and will not affectthe midplane or the other chassis level infrastructure which is moredifficult to repair. The other RSM modules and the chassisinfrastructure are unaffected and may continue to operate untilreplacement parts and service are arranged.

The bus bars also enhance the structural rigidity of the connectors. Byconnecting all or some of the connectors together, the connectorsreinforce each other by transferring forces through the bus bars. Anyforce on one connector, for example when removing or installing an RMSwill be transferred to the neighboring connectors through the bus barswhich will help to hold the connector in place. The bus bars may havesome form of insulator coating along the entire length except wherecontact is made with a memory card finger. Covering the exposed surfacesof the bus bars reduces the chance of an accidental shorting caused bydebris or other loos articles in the housing. Internal surfaces wherethe RSM module fingers mate with the connector are exposed for powerconduction.

FIG. 9 shows an example of how the quarter circle interface connectors182 connect a midplane 106 connector 183 to a card edge connector 181.The midplane has an array of electrical connector slots installed ontoor into the midplane PCB 106. These slots have an array e.g. 30 on eachside, of electrical contacts 336. The midplane slot contacts engage withcorresponding contacts on the interface connector. The slots arearranged vertically upward so that the interface connector is pusheddown into the midplane connector. The interface connector may be wedgedinto place by angled sides of the midplane connector or a latch, tab,lock, or similar mechanism may be used. The card connector 181 slidesinto place in a similar way on the other side of the interface connector182. The card connector may also be attached to the midplane withlatches, tabs or some other feature to prevent horizontal motion andrelease from the interface connector.

In an alternative embodiment, there is no midplane connector slot.Instead the midplane PCB has a set of pads or lands 340 to connect tothe interface connector and the interface connector has a series ofmating tail connectors. The interface connector may then be solderedinto place on the midplane PCB to make connections and hold theinterface connector in place. The described connector topology may beused with either a card edge or a solder tail connection to the midplanestructures. The card edge approach provides mechanical flexibility,particularly for dual port type configurations, while the solder tailconnection will have superior signal integrity, higher mechanicalstrength and fewer failure modes. As shown, the horizontal orientationof the midplane eliminates the need to design cavities into the midplaneto accommodate air flow. This greatly simplifies midplane design andsignal routing.

FIG. 10 is a side view diagram of the rear edge an RSM, such as thememory card described above. While the memory card has a very specificshape, the features are those that may be formed using conventional PCBmaterials and techniques. The edge of the card 302 has a row of contacts306 that may be formed from wiring layers in or on the PCB. Theconnectors may be copper or plated copper with gold, silver or any otherdesired material. The top and the bottom of the memory card have fingers308 formed by creating a slot 304 near the top and bottom of the edge ofthe card. Each slot is specifically shaped to receive a correspondingbus bar 322, 324. A metal connector 330 in each slot establishes a powerconnection with the respective bus bar and conducts the power to wiringlayers of the memory card and from there to the chips and othercomponents mounted on the memory card. These may be manufactured intothe PCB or attached to the PCB. Attachment to the PCB reduces the stresson the PCB due to flexing.

The upper and lower slots have tapered guide surfaces on the upper 342and lower 344 sides of each slot. The bus bars have curved edges and areflattened to slide into the corresponding slots. The tapered guidesurfaces guide the edge of the card around the curved edges of the busbar to align the card edge vertically with respect to the bus bars. Theconnector slots 304 also have a rear stop 338. This rear may be arrangedto align with the rear stop of the connector slots 318 so that the busbar hits the rear stop on the card edge at about the same position thatthe card edge finger 308 hits the rear of the connector stop 318. Inthis way the card is fixed in position and prevented from any furthermovement into the connectors.

The card edge connector on the RSM provides some advantages compared toa card edge connector on the backplane or midplane. For example, the PCBof the quarter circle interface connector may be made very thin. Athinner PCB is simpler and less expensive to manufacture and savesweight and material costs. The card edge connector on the RSM requiresthat the card connector 181 be designed to the width of the RSM module.If different size PCBs are to be used for different RSM modules, thenthe card connector 181 may be adapted to accommodate this change.

FIG. 11 is a side view diagram of a quarter circle connector 382attached to system midplane 380 and to a memory card connector 381. Thisquarter circle connector is configured to provide a particular z-height383 between the memory card connector and the midplane PCB.

FIG. 12 is a side view diagram of a similar quarter circle connector 385attached to a midplane PCB 387 and a memory card connector 384. Thisquarter circle connector is configured to provide a different smallerz-height 386 to accommodate different dimensions of a memory card. ThePCB of the interface connector 382, 385 structures makes it possible toeasily accommodate various z-height offsets from the midplane. Only theinterface connector is changed. If the midplane uses card connectorslots to attach to the interface connector, then different interfaceconnectors 382, 385 may be quickly exchanged for different memory cardconfigurations in the chassis.

FIG. 13 is an isometric view of an alternative quarter circle interfaceconnector. In this example a memory card 402 has an edge connector tomate with a card connector 404. As described above the card edge has arow of contacts 406 on one or both side and slots 418 to slide over andengage bus bars 406. The card connector is coupled to a quarter circleinterface connector 410. The interface connector 410 has a quartercircle wiring layer that extends horizontally away from the cardconnector and then vertically downward to a set of contacts 412 thatmake contact with another component such as a slot connector or amidplane or other PCB. The interface connector 410 also has a quartercircle wiring layer that extends in the opposite direction. This wiringlayer extends horizontally away from the memory card and then verticallyupward to contacts 414 on the interface connector for a different PCB,slot or other connection.

The illustrated interface connector allows a memory board to besimultaneously connected to two different components. The twoconnections may allow one part of the memory to connect to one componentand another part of the memory to connect to a different component.Alternatively, all of the memory may connect to both components. The twocomponents may be provided for redundancy or the two components may bedifferent types of components. One component may be a switchinginterface and the other component may be a compute device or a differenttype of switching interface. There may be multiple computing devices toshare the memory.

FIG. 14 is an isometric diagram of an alternative memory card connectorand interface connector in which the two components are combined into asingle interface connector structure. As shown a midplane (also referredto herein as a PCB or plane board) 502 or other horizontal PCB ismounted within a chassis (not shown). There is an array, for example, 32of interface connectors 504 attached in a row to the PCB. The interfaceconnectors may be attached directly to the PCB, e.g. by soldering ontopads, or inserted into a socket as shown above. Each interface connectorhas a slot 510 with an array of electrical contacts 506 to receive theedge of a memory card and make an electrical connection with the memorycard.

The interface connectors also have legs 508 on one or both sides of eachconnector to stabilize the position of the connector on the PCB. Theselegs may rest against the PCB and may also be attached using solder,pins, tabs, latches, screws through the PCB, or another mechanism.

The slot has angled sides so that the memory card is guided intoposition horizontally and vertically and so that the memory card is alsowedged into place within the slot. In this example, there are noseparate bus bars. The power connections are made within the slot. Inthe same way, the previously described examples may also be made withoutbus bars. The bus bars improve the strength of the connector array butalso add cost, complexity and the risk of short circuits and electricalshock.

FIG. 15 is an isometric view of the same interface connectors 504mounted to the PCB 502 as seen from the opposite side. As with the otherexamples, the connectors are parallel and in a single row. There is aspace between each connector to allow airflow between them. As a result,cooling air may flow across and between the memory cards and continuepast the connectors to the rear of the enclosure.

The interface connectors of FIGS. 14 and 15 may be used by sliding amemory card into position from the front of the enclosure. The card edgeconnector slides into the slot and makes electrical contact. The slotholds the card vertically orthogonal to the plane board 502 upon whichthe connector is attached. The card may also be held in position bygrooves or slots in the enclosure at the other end of the memory card.Handles 316 at the front of the enclosure allow memory cards to bepulled out so that other memory cards may be pushed in.

FIG. 16 is a block diagram of a computing device 100 in accordance withone implementation. The computing device 100 houses a system board 2.The board 2 may include a number of components, including but notlimited to a processor 4 and at least one communication package 6. Thecommunication package is coupled to one or more antennas 16. Theprocessor 4 is physically and electrically coupled to the board 2.

Depending on its applications, computing device 100 may include othercomponents that may or may not be physically and electrically coupled tothe board 2. These other components include, but are not limited to,volatile memory (e.g., DRAM) 8, non-volatile memory (e.g., ROM) 9, flashmemory (not shown), a graphics processor 12, a digital signal processor(not shown), a crypto processor (not shown), a chipset 14, an antenna16, a display 18 such as a touchscreen display, a touchscreen controller20, a battery 22, an audio codec (not shown), a video codec (not shown),a power amplifier 24, a global positioning system (GPS) device 26, acompass 28, an accelerometer (not shown), a gyroscope (not shown), aspeaker 30, a camera 32, a microphone array 34, and a mass storagedevice (such as hard disk drive) 10, compact disk (CD) (not shown),digital versatile disk (DVD) (not shown), and so forth). Thesecomponents may be connected to the system board 2, mounted to the systemboard, or combined with any of the other components.

The communication package 6 enables wireless and/or wired communicationsfor the transfer of data to and from the computing device 100. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication package 6 may implementany of a number of wireless or wired standards or protocols, includingbut not limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+,HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, Ethernetderivatives thereof, as well as any other wireless and wired protocolsthat are designated as 3G, 4G, 5G, and beyond. The computing device 100may include a plurality of communication packages 6. For instance, afirst communication package 6 may be dedicated to shorter range wirelesscommunications such as Wi-Fi and Bluetooth and a second communicationpackage 6 may be dedicated to longer range wireless communications suchas GPS, EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.

The computing system may be configured to be used as the system module.The computing system also reflects the entire rack-mount memory systemwhere the mass memory is formed from multiple memory cards, asdescribed. The memory system may have multiple iterations of thecomputing system within a single enclosure for each system module andalso for the overall system.

In various implementations, the computing device 100 may be anentertainment front end unit or server, a music or video editing stationor back end, a cloud services system, a database, or any other type ofhigh performance or high density storage or computing system.

Embodiments may be include one or more memory chips, controllers, CPUs(Central Processing Unit), microchips or integrated circuitsinterconnected using a motherboard, an application specific integratedcircuit (ASIC), and/or a field programmable gate array (FPGA).

References to “one embodiment”, “an embodiment”, “example embodiment”,“various embodiments”, etc., indicate that the embodiment(s) sodescribed may include particular features, structures, orcharacteristics, but not every embodiment necessarily includes theparticular features, structures, or characteristics. Further, someembodiments may have some, all, or none of the features described forother embodiments.

In the following description and claims, the term “coupled” along withits derivatives, may be used. “Coupled” is used to indicate that two ormore elements co-operate or interact with each other, but they may ormay not have intervening physical or electrical components between them.

As used in the claims, unless otherwise specified, the use of theordinal adjectives “first”, “second”, “third”, etc., to describe acommon element, merely indicate that different instances of likeelements are being referred to, and are not intended to imply that theelements so described must be in a given sequence, either temporally,spatially, in ranking, or in any other manner.

The drawings and the forgoing description give examples of embodiments.Those skilled in the art will appreciate that one or more of thedescribed elements may well be combined into a single functionalelement. Alternatively, certain elements may be split into multiplefunctional elements. Elements from one embodiment may be added toanother embodiment. For example, orders of processes described hereinmay be changed and are not limited to the manner described herein.Moreover, the actions of any flow diagram need not be implemented in theorder shown; nor do all of the acts necessarily need to be performed.Also, those acts that are not dependent on other acts may be performedin parallel with the other acts. The scope of embodiments is by no meanslimited by these specific examples. Numerous variations, whetherexplicitly given in the specification or not, such as differences instructure, dimension, and use of material, are possible. The scope ofembodiments is at least as broad as given by the following claims.

The following examples pertain to further embodiments. The variousfeatures of the different embodiments may be variously combined withsome features included and others excluded to suit a variety ofdifferent applications. Some embodiments pertain to an apparatus thatincludes in one example a horizontal plane board having a plurality ofmemory connectors aligned in a row and a plurality of externalinterfaces, a plurality of memory cards, each having an edge connectorat one end of the memory card to connect to a respective memoryconnector of the board, each memory card extending horizontally parallelto each other memory card and extending vertically and orthogonally fromthe board, and a plurality of interface connectors each to connect anedge connector to a respective board connector, the interface connectorsextending horizontally from the one end of the memory cards andvertically to the respective plane board connector.

In further embodiments the interface connector comprises a printedcircuit board and the printed circuit board is vertically aligned withthe memory card to allow airflow between the parallel memory cards andbetween the vertically aligned interface connectors.

In further embodiments the interface connectors are parallel to eachother and extending vertically from the plane board.

In further embodiments each memory connector comprises pads on the planeboard and wherein each interface connector is soldered to the respectivepads on the plane board.

In further embodiments each memory connector comprises sockets andwherein each interface connector is inserted into the respective socket.

In further embodiments each interface connector comprises a socket andeach memory card edge connector is inserted into the respectiveinterface connector socket.

In further embodiments the sockets further comprise a bus bar thatextends through the sockets to provide a common power supply to multiplememory cards.

In further embodiments each socket comprises a ledge to support the busbar in one direction and a stop at one end of the ledge to preventmovement of the bus bar in a second orthogonal direction.

In further embodiments the memory card edge connector comprises a slotinto which the bus bar is placed when the edge connector is insertedinto a socket, wherein the slot is defined, in part, by a finger whichengages the bus bar on one side.

Further embodiments include a second bus bar that extends through thesockets, wherein the memory card edge connector comprises a secondfinger to engage the second bus bar on a side opposite the side on whichthe first finger engages the first bus bar.

In further embodiments the interface connector socket comprises a guideto receive the finger, the guide including a stop so that a memory cardis limited in horizontal movement into the connector by the finger beingpushed against the stop.

Further embodiments include an enclosure configured to mount in a rack,the enclosure having a front configured to receive airflow and a rearconfigured for cabling, wherein the horizontal plane board is mountedinside the enclosure having a first side and a second opposite side, thefirst side being attached to the memory cards, wherein the memory cardsextend from the from the front of the enclosure to attach to thehorizontal plane board, a power supply proximate the rear of theenclosure and the first side of the horizontal plane board to providepower to the memory cards through the memory card connectors and havinga fan to pull air from the front of the enclosure between the memorycards and to push air out the rear of the enclosure, and a cablinginterface at the rear of the enclosure coupled to the externalconnectors.

In further embodiments the memory cards each comprise a plurality ofmemory chips and a memory controller chip coupled to each of the memorychips and to the connector.

Some embodiments pertain to a memory card connector that includes afirst multiple contact connector having a plurality of pins configuredto be attached to a horizontal plane board so that the memory cardconnector extends orthogonal to the plane board, a plurality of legsextending from the memory card connector configured to rest against thehorizontal surface of the plane board to stabilize the position of thememory card connector, and a second multiple contact connector having asocket configured to receive an edge connector of a memory card so thatthe memory card extends vertically and orthogonally from the plane boardand away from the edge of the memory card and the connector across a topsurface of the plane board.

In further embodiments the memory card connector is configured to beattached to the plane board aligned in a row to connect to parallelmemory cards across the row and is further configured to allow airflowbetween the parallel memory cards and between the vertically alignedmemory card connectors.

In further embodiments the first connector is orthogonal to the secondconnector.

Further embodiments include a printed circuit board between the firstconnector and the second connector having quarter-circle wiring layersto connect the first connector to the second connector.

Some embodiments pertain to an apparatus that includes an enclosureconfigured to mount in a rack, the enclosure having a front configuredto receive airflow and a rear configured for cabling, a horizontal planeboard in the enclosure having a plurality of memory connectors and aplurality of external interfaces, the horizontal plane board having afirst side and a second opposite side, a plurality of memory cards, eachhaving an edge connector on a vertical edge at one end of the respectivememory card to connect through a respective quarter-circle connector tothe horizontal plane board, each memory card extending parallel to eachother memory card from the front of the enclosure and extendingorthogonally from the first side of the horizontal plane board, a powersupply proximate the rear of the enclosure and the first side of thehorizontal plane board to provide power to the memory cards through thequarter-circle connectors and having a fan to pull air from the front ofthe enclosure between the memory cards and to push air out the rear ofthe enclosure, and a cabling interface at the rear of the enclosurecoupled to the external connectors, wherein the quarter-circleconnectors each have a first connection interface to connect to arespective memory card edge connector and a second connection interfaceto connect to a respective board connector of the plane board, thequarter-circle connectors extending from the vertical edge of therespective memory card horizontally and vertically to the respectiveplane board connector, so that the first connector is orthogonal to thesecond connector.

In further embodiments the quarter-circle connector comprises a printedcircuit board and the printed circuit board is vertically aligned withthe memory card to allow airflow between the parallel memory cards andbetween the vertically aligned quarter-circle connectors.

In further embodiments the first connector of each quarter-circleconnector comprises a socket and each memory card edge is inserted intothe respective first connector socket.

The invention claimed is:
 1. An apparatus comprising: a midplane printedcircuit board (PCB); a plurality of connectors aligned in a row andmounted on the midplane PCB, each of the plurality of connectorsincluding a slot extending orthogonally from the midplane PCB, the slotincluding electrical contacts; and a plurality of solid state drive(SSD) memory cards, each of the plurality of SSD memory cards having aconnector at one end of the SSD memory card to be received by the slotof one of the plurality of connectors mounted on the midplane PCB;wherein the slot of each of the plurality of connectors is to receivethe connector of one of the plurality of the SSD memory cards in adirection parallel to the midplane PCB, each of the plurality of SSDmemory cards to extend parallel to one another and to extendorthogonally from the midplane PCB.
 2. The apparatus of claim 1,wherein: each of the plurality of SSD memory cards includes aruler-shaped memory card including a first edge, a second edge that isshorter than the first edge, and a thickness that is less than a lengthof the second edge, the first edge to extend parallel to the midplanePCB and the second edge to extend orthogonally from the midplane PCB. 3.The apparatus of claim 1, wherein: each of the plurality of SSD memorycards includes a handle on an end opposite the end having the connector.4. The apparatus of claim 1, further comprising: an enclosure toencompass the midplane PCB, the plurality of connectors, and theplurality of SSD memory cards; and a plurality of fans in the enclosureto pull air from a front of the enclosure to a rear of the enclosure. 5.The apparatus of claim 4, wherein the plurality of fans are mountedbetween the plurality of SSD memory cards and the rear of the enclosure.6. The apparatus of claim 4, wherein the enclosure includes a bottomplate to hold the plurality of SSD memory cards parallel to one another.7. The apparatus of claim 1, wherein: the plurality of SSD memory cardsincludes NAND flash SSD memory cards.
 8. An apparatus comprising: ahorizontal midplane printed circuit board (PCB); a plurality ofconnectors aligned in a row and mounted on the horizontal midplane PCB,each of the plurality of connectors including a slot to horizontallyreceive a connector of a solid state drive (SSD) memory card in adirection parallel to the midplane PCB, the slot extending verticallyand orthogonally from the horizontal midplane PCB, the slot includingelectrical contacts to couple with second electrical contacts of theconnector of the SSD memory card; and wherein the SSD memory cardincludes the connector at one end of the SSD memory card to be receivedby the slot, the SSD memory card to extend orthogonally from thehorizontal midplane PCB when the connector is received by the slot. 9.The apparatus of claim 8, wherein: the SSD memory card includes aruler-shaped memory card including a first edge, a second edge that isshorter than the first edge, and a thickness that is less than a lengthof the second edge, the first edge of to extend parallel to the midplanePCB and the second edge to extend orthogonally from the midplane PCB.10. The apparatus of claim 8, wherein: the SSD memory card includes ahandle on an end opposite the end having the connector.
 11. Theapparatus of claim 8, further comprising: an enclosure to encompass thehorizontal midplane PCB, the plurality of connectors, and the SSD memorycard; and a plurality of fans in the enclosure to pull air from a frontof the enclosure to a rear of the enclosure.
 12. The apparatus of claim11, wherein the plurality of fans are mounted between the plurality ofconnectors and the rear of the enclosure.
 13. The apparatus of claim 8,wherein: the SSD memory card includes a NAND flash SSD memory card. 14.A system including: a rack-mount chassis; a printed circuit board (PCB)in the rack-mount chassis; a row of connectors mounted on the PCB, eachconnector of the row including a slot extending orthogonally from thePCB, the slot including electrical contacts; and a plurality of solidstate drive (SSD) memory cards, each of the plurality of SSD memorycards having a connector at one end of the memory card to be received bythe slot of one of the row of connectors, each of the plurality of SSDmemory cards having a first edge to extend parallel to one another andparallel to the PCB and a second shorter edge to extend orthogonallyfrom the PCB; wherein the slot of each connector of the row is toreceive the connector of one of the plurality of the SSD memory cards ina direction parallel to the PCB.
 15. The system of claim 14, furthercomprising: one or more PCIe (Peripheral Component Interconnect express)switches coupled with the plurality of SSD memory cards.
 16. The systemof claim 14, further comprising: a NVMe (non-volatile memory express)interface coupled with the plurality of SSD memory cards.
 17. The systemof claim 14, wherein: each of the plurality of SSD memory cards includesa ruler-shaped memory card including the first edge, the second edgethat is shorter than the first edge, and a thickness that is less than alength of the second edge.
 18. The system of claim 14, wherein: each ofthe plurality of SSD memory cards includes a handle on an end oppositethe end having the connector.
 19. The system of claim 14, furthercomprising: a plurality of fans in the rack-mount chassis to pull airfrom a front of the chassis to a rear of the chassis.
 20. The system ofclaim 19, wherein the plurality of fans are mounted between theplurality of SSD memory cards and the rear of the rack-mount chassis.21. The system of claim 14, wherein the rack-mount chassis includes abottom plate to hold the plurality of SSD memory cards parallel to oneanother.
 22. The system of claim 14, wherein: the plurality of SSDmemory cards includes NAND flash SSD memory cards.
 23. The system ofclaim 14, wherein the PCB includes a midplane.